1. Field of the Invention
The present invention relates to an initial position setting method of an optical pickup for reproducing signals recorded on disks having lead-in areas which start at different positions with respect to the center of the disk. The invention particularly relates to an initial position setting method of an optical pickup capable of swiftly moving the optical pickup to a start position of a lead-in area of an optical disk loaded in an optical player, based on disk recognition, and to an optical disk player using the same.
2. Description of Related Art
Generally, an optical disk recording and reproducing apparatus adopts a digital recording method which uses a disk on which an analog signal is sampled and converted into a digital signal so as to be finally recorded as a groove-shaped pattern known as a pit. In a structure of the disk, grooves which have different lengths (pits) are formed on concentric circles at a portion on which digital signals are recorded. The digital signals are recorded according to the varying position and length of the grooves. To read out the thusly-recorded signals, an optical pickup is required. The optical pickup projects a laser beam to the pits, and converts the reflected light into an electrical signal to thereby reproduce a signal, without the optical pickup contacting the disk. Here, the disk rotates at a constant linear velocity (CLV) or at a constant angular velocity (CAV) and the pickup moves from an inner circumference toward an outer circumference.
FIG. 1A shows a signal recording area of a general compact disk, and FIG. 1B shows a signal recording area of a general mini-disk. The signal recording areas of each of the disks comprises three sub-areas having a table of contents (TOC) area (B), a program area (C) and a lead-out area (D). In the case of an audio disk, the TOC area (B) contains a list of contents such as an address (a position on the disk) and a playing time of each audio program (such as a song) and the total playing time of all the audio programs which are recorded on the disk. The program area (C) is an area on which audio information is recorded, and the lead-out area is a signal area representing an end of the program, on which a lead-out signal, which is a repeat pulse of a predetermined frequency, is recorded.
The positions of the above-described three areas will be described below in more detail. In the case of the FIG. 1A compact disk, the lead-in TOC area (B) starts from a position which is distant by 23 mm from the center (A), and the program area (C) occupies a space starting from a position which is distant by 25 mm from the center (A) and extending to another position which is distant by 58 mm therefrom. The lead-out area (D) starts from an end position of the program area (C). In the case of the FIG. 1B mini-disk, the TOC area (B) starts from a position which is located 14.5 mm from the center (A), the program area (C) occupies a space starting from a position which is located 16.5 mm from the center (A) and extending to another position which is located 30.5 mm therefrom. The lead-out area (D) starts from an end position of the program area (C).
Recently, in most systems which reproduce a compact disk or a mini-disk having the above structure, when a disk is loaded, a pickup apparatus is immediately moved to a TOC area of the disk to read out information contained in the TOC area and to display the number of the audio programs (such as songs) contained on the disk and the total playing time. Therefore, the initial position of the optical pickup apparatus is set so that the optical pickup is positioned at a start position of the TOC area in the loaded disk at the time when the disk is initially loaded. However, when using a recently-developed product which accommodates both a compact disk and a mini-disk, since the start positions of the TOC areas of the compact disk and the mini-disk are different from each other as described above, it takes a long time to recognize which type of disk has been loaded and to find the initial position of the corresponding disk. For this reason, an interval from the loading of the disk to the start of reproducing the signal is long.